Regulation of the expression of the nickel uptake system in Vibrio cholerae by iron and heme via Fur

ABSTRACTVibrio choleraeis the causative agent of the deadly diarrheal disease cholera. As part of its life cycle,V. choleraepersists in marine environments, where it forms surface-attached communities commonly described as biofilms. Evidence indicates that these biofilms constitute the infectious form of the pathogen during outbreaks. Previous work has shown that biofilm-derivedV. choleraecells, even when fully dispersed from the biofilm matrix, are vastly more infectious than planktonic (free-living) cells. Here, we sought to identify factors that contribute to biofilm-induced hyperinfectivity inV. cholerae, and we present evidence for one aspect of the molecular basis of this phenotype. We identified proteins upregulated during growth in biofilms and determined their contributions to the hyperinfectivity phenotype. We found that PstS2, the periplasmic component of the Pst2 phosphate uptake system, was enriched in biofilms. Another gene in thepst2locus was transcriptionally upregulated in biofilms. Using the infant mouse model, we found that mutation of twopst2components resulted in impaired colonization. Importantly, deletion of the Pst2 inner membrane complex caused a greater colonization defect after growth in a biofilm compared to shaking culture. Based on these data, we propose thatV. choleraecells in biofilms upregulate the Pst2 system and therefore gain an advantage upon entry into the host. Further characterization of factors contributing to biofilm-induced hyperinfectivity inV. choleraewill improve our understanding of the transmission of the bacteria from natural aquatic habitats to the human host.

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Crystal structure of the putative peptide-binding protein AppA from Clostridium difficile

Acta Crystallographica Section F Structural Biology Communications ◽

10.1107/s2053230x1900178x ◽

2019 ◽

Vol 75 (4) ◽

pp. 246-253 ◽

Cited By ~ 3

Author(s):

Adam Hughes ◽

Samuel Wilson ◽

Eleanor J. Dodson ◽

Johan P. Turkenburg ◽

Anthony J. Wilkinson

Keyword(s):

Crystal Structure ◽

Bacillus Subtilis ◽

Clostridium Difficile ◽

Binding Protein ◽

Peptide Binding ◽

Protein Sequences ◽

Receptor Protein ◽

Uptake System ◽

Receptor Proteins ◽

Nickel Uptake

Peptides play an important signalling role in Bacillus subtilis, where their uptake by one of two ABC-type oligopeptide transporters, Opp and App, is required for efficient sporulation. Homologues of these transporters in Clostridium difficile have been characterized, but their role, and hence that of peptides, in regulating sporulation in this organism is less clear. Here, the oligopeptide-binding receptor proteins for these transporters, CdAppA and CdOppA, have been purified and partially characterized, and the crystal structure of CdAppA has been determined in an open unliganded form. Peptide binding to either protein could not be observed in Thermofluor assays with a set of ten peptides of varying lengths and compositions. Re-examination of the protein sequences together with structure comparisons prompts the proposal that CdAppA is not a versatile peptide-binding protein but instead may bind a restricted set of peptides. Meanwhile, CdOppA is likely to be the receptor protein for a nickel-uptake system.

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FeoA and FeoC Are Essential Components of the Vibrio cholerae Ferrous Iron Uptake System, and FeoC Interacts with FeoB

Journal of Bacteriology ◽

10.1128/jb.00738-13 ◽

2013 ◽

Vol 195 (21) ◽

pp. 4826-4835 ◽

Cited By ~ 37

Author(s):

E. A. Weaver ◽

E. E. Wyckoff ◽

A. R. Mey ◽

R. Morrison ◽

S. M. Payne

Keyword(s):

Vibrio Cholerae ◽

Ferrous Iron ◽

Iron Uptake ◽

Uptake System ◽

Iron Uptake System ◽

Essential Components

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Nickel Represses the Synthesis of the Nickel Permease NixA of Helicobacter pylori

Journal of Bacteriology ◽

10.1128/jb.188.4.1245-1250.2006 ◽

2006 ◽

Vol 188 (4) ◽

pp. 1245-1250 ◽

Cited By ~ 35

Author(s):

Lutz Wolfram ◽

Elvira Haas ◽

Peter Bauerfeind

Keyword(s):

Helicobacter Pylori ◽

Translational Regulation ◽

Regulatory Protein ◽

Nickel Concentration ◽

Uptake System ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Nickel Uptake ◽

Protective Reaction ◽

H Pylori

ABSTRACT Nickel acquisition is necessary for urease activity, a major virulence factor of the human gastric pathogen Helicobacter pylori. NixA was identified as a specific nickel uptake system in this organism. Addition of small amounts of nickel to media strongly stimulates urea hydrolysis. On the other hand, high nickel concentrations are deleterious to cell growth. As a possible protective reaction, nickel uptake seems to be reduced in H. pylori grown in nickel-rich media. These observations led to investigations of regulation of the expression of the nickel permease NixA. We found that increasing the nickel concentration in media reduced the amount of NixA. In order to address the question of whether this phenomenon was subject to transcriptional or translational regulation, we quantified nixA mRNA from H. pylori by real-time PCR. The amount of nixA mRNA was gradually reduced five- to sevenfold in a time- and concentration-dependent manner. Repression could be measured as soon as 5 min after nickel addition, and the maximum repression occurred after 20 to 30 min. The maximum repression was obtained with an external nickel concentration of 100 μM. The observed nickel repression of NixA was dependent on nikR encoding the nickel-responsive regulatory protein NikR. In conclusion, we demonstrated that synthesis of the NixA nickel permease of H. pylori shows nickel-responsive regulation mediated by NikR to maintain the balance between effective nickel acquisition and a toxic overload.

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Identification and Characterization of the Nickel Uptake System for Urease Biogenesis in Streptococcus salivarius 57.I

Journal of Bacteriology ◽

10.1128/jb.185.23.6773-6779.2003 ◽

2003 ◽

Vol 185 (23) ◽

pp. 6773-6779 ◽

Cited By ~ 35

Author(s):

Yi-Ywan M. Chen ◽

Robert A. Burne

Keyword(s):

Urease Activity ◽

Streptococcus Thermophilus ◽

Uptake System ◽

Streptococcus Salivarius ◽

Reading Frame ◽

Related Organism ◽

Nickel Uptake ◽

Insertional Inactivation ◽

Cobalamin Biosynthesis

ABSTRACT Ureases are multisubunit enzymes requiring Ni2+ for activity. The low pH-inducible urease gene cluster in Streptococcus salivarius 57.I is organized as an operon, beginning with ureI, followed by ureABC (structural genes), and ureEFGD (accessory genes). Urease biogenesis also requires a high-affinity Ni2+ uptake system. By searching the partial genome sequence of a closely related organism, Streptococcus thermophilus LMG18311, three open reading frame (ORFs) homologous to those encoding proteins involved in cobalamin biosynthesis and cobalt transport (cbiMQO) were identified immediately 3′ to the ure operon. To determine whether these genes were involved in urease biogenesis by catalyzing Ni2+ uptake in S. salivarius, regions 3′ to ureD were amplified by PCRs from S. salivarius by using primers identical to the S. thermophilus sequences. Sequence analysis of the products revealed three ORFs. Reverse transcriptase PCR was used to demonstrate that the ORFs are transcribed as part of the ure operon. Insertional inactivation of ORF1 with a polar kanamycin marker completely abolished urease activity and the ability to accumulate 63Ni2+ during growth. Supplementation of the growth medium with NiCl2 at concentrations as low as 2.5 μM partially restored urease activity in the mutant. Both wild-type and mutant strains showed enhanced urease activity when exogenous Ni2+ was provided at neutral pH. Enhancement of urease activity by adding nickel was regulated at the posttranslational level. Thus, ORF1, ORF2, and ORF3 are part of the ure operon, and these genes, designated ureM, ureQ, and ureO, respectively, likely encode a Ni2+-specific ATP-binding cassette transporter.

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Impact of Na+-Translocating NADH:Quinone Oxidoreductase on Iron Uptake and nqrM Expression in Vibrio cholerae

Journal of Bacteriology ◽

10.1128/jb.00681-19 ◽

2019 ◽

Vol 202 (3) ◽

Author(s):

Shubhangi Agarwal ◽

Melanie Bernt ◽

Charlotte Toulouse ◽

Hannes Kurz ◽

Jens Pfannstiel ◽

...

Keyword(s):

Vibrio Cholerae ◽

Iron Uptake ◽

Iron Homeostasis ◽

Mrna Level ◽

Strong Impact ◽

Substrate Uptake ◽

Uptake System ◽

Content Type ◽

Respiratory Enzyme ◽

Nadh:Quinone Oxidoreductase

ABSTRACT The Na+ ion-translocating NADH:quinone oxidoreductase (NQR) from Vibrio cholerae is a membrane-bound respiratory enzyme which harbors flavins and Fe-S clusters as redox centers. The NQR is the main producer of the sodium motive force (SMF) and drives energy-dissipating processes such as flagellar rotation, substrate uptake, ATP synthesis, and cation-proton antiport. The NQR requires for its maturation, in addition to the six structural genes nqrABCDEF, a flavin attachment gene, apbE, and the nqrM gene, presumably encoding a Fe delivery protein. We here describe growth studies and quantitative real-time PCR for the V. cholerae O395N1 wild-type (wt) strain and its mutant Δnqr and ΔubiC strains, impaired in respiration. In a comparative proteome analysis, FeoB, the membrane subunit of the uptake system for Fe2+ (Feo), was increased in V. cholerae Δnqr. In this study, the upregulation was confirmed on the mRNA level and resulted in improved growth rates of V. cholerae Δnqr with Fe2+ as an iron source. We studied the expression of feoB on other respiratory enzyme deletion mutants such as the ΔubiC mutant to determine whether iron transport is specific to the absence of NQR resulting from impaired respiration. We show that the nqr operon comprises, in addition to the structural nqrABCDEF genes, the downstream apbE and nqrM genes on the same operon and demonstrate induction of the nqr operon by iron in V. cholerae wt. In contrast, expression of the nqrM gene in V. cholerae Δnqr is repressed by iron. The lack of functional NQR has a strong impact on iron homeostasis in V. cholerae and demonstrates that central respiratory metabolism is interwoven with iron uptake and regulation. IMPORTANCE Investigating strategies of iron acquisition, storage, and delivery in Vibrio cholerae is a prerequisite to understand how this pathogen thrives in hostile, iron-limited environments such as the human host. In addition to highlighting the maturation of the respiratory complex NQR, this study points out the influence of NQR on iron metabolism, thereby making it a potential drug target for antibiotics.

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In vivo Production of Soluble Inorganic Pyrophosphatases in Two Strains of Vibrio cholerae

Bangladesh Journal of Microbiology ◽

10.3329/bjm.v24i1.1235 ◽

1970 ◽

Vol 24 (1) ◽

pp. 38-41

Author(s):

Taslima Taher Lina ◽

Mohammad Ilias

Keyword(s):

Vibrio Cholerae ◽

Specific Activity ◽

Experimental Conditions ◽

Environmental Strain ◽

Cell Extracts ◽

Atcc Strain ◽

The Family ◽

Effects Of Ph ◽

Vibrio Cholerae O1

The in vivo production of soluble inorganic pyrophosphatases (PPases) was investigated in two strains, namely, Vibrio cholerae EM 004 (environmental strain) and Vibrio cholerae O1 757 (ATCC strain). V. cholerae is known to contain both family I and family II PPase coding sequences. The production of family I and family II PPases were determined by measuring the enzyme activity in cell extracts. The effects of pH, temperature, salinity of the growth medium on the production of soluble PPases were studied. In case of family I PPase, V. cholerae EM 004 gave the highest specific activity at pH 9.0, with 2% NaCl + 0.011% NaF and at 37°C. The strain V. cholerae O1 757 gave the highest specific activity at pH 9.0, with media containing 0% NaCl and at 37°C. On the other hand, under all the conditions family II PPase did not give any significant specific activity, suggesting that the family II PPase was not produced in vivo in either strains of V. cholerae under different experimental conditions. Keywords: Vibrio cholerae, Pyrophosphatases (PPases), Specific activityDOI: http://dx.doi.org/10.3329/bjm.v24i1.1235 Bangladesh J Microbiol, Volume 24, Number 1, June 2007, pp 38-41

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